<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
    <style>
        p{
            font-size: 14px;
            line-height: 1em;
        }
        big{
            font-size: 250%;
            line-height: 1em;
            /*【1】一定要注意，line-height可以继承，但是参照字体是当前元素;*/
            /*此处设置的em，也可以设置为数字因子1，这样子代都会继承这个因子，然后参考*/
            /*各自字体换算。*/
        }
        span{
            /*border: 1px solid black;*/
            padding: 14px;
        }
    </style>
</head>
<body>
<p>this place will see a lot of words in this p tag
    <big>this place will see a lot of word</big>
</p>
<span>
    this text will see  a lot of ,and we can find out
    this text will see  a lot of ,and we can find out
    this text will see  a lot of ,and we can find out
    this text will see  a lot of ,and we can find out
</span>
</body>
</html>